Philadelphia University
Faculty of Information Technology
Lecturer: Dr. Nameer N. EL-Emam
Department of CS
Internal Examiner: Dr. Raad Alwan
Marking Scheme
Coordinator: Dr. Nameer N. EL-Emam
Module Name: Simulation and Modelling First Exam Semester one of the academic year:
Module Number: 750472
2016-2017
Date: 22/11/2016 Time 50 Min.
Basic Part:
Objective: This part aims to show student capability to answer the understanding knowledge.
Q1/ (7-marks): Answer the following MCQs:
1 . Simulation:
a) does not guarantee optimality.
b) is flexible and does not require the assumptions of theoretical models.
c) allows testing of the system without affect in the real system.
d) All of the alternatives are correct.
2. A simulation model used in situations where the state of the system at one point in time does not affect the state of
the system at future points in time is called a:
a) dynamic simulation model.
b) static simulation model.
c) steady state simulation model.
d) discrete event simulation model.
3.When events occur at discrete points in time:
a) a simulation clock is required.
b) the simulation advances to the next event.
c) the model is a discrete event simulation.
d) All of the alternatives are correct.
4.The process of determining that the computer procedure that performs the simulation calculations is logically correct is called:
a) implementation.
b) validation.
c) verification.
d) repetition.
5 .Numerical values that appear in the mathematical relationships of a model and are considered known and remain constant
over all trials of a simulation are:
a) parameters.
b) probabilistic input.
c) controllable input.
d) events.
6. The first step in simulation is to:
a) set up possible courses of action for testing.
b) construct a numerical model.
c) validate the model.
d) define the problem.
7 . Which of the following statements is INCORRECT regarding the advantages of simulation?
a) Simulation is relatively easy to explain and understand.
b) Simulation guarantees’ an optimal solution.
c) Simulation models are flexible.
d) A simulation model provides a convenient experimental laboratory for the real system.
Familiar Part:
Objective: This part aims to show student capability to find solution of the problem (problem solving approach).
Q2/ (8 marks): Assume that we have the following time analysis for the behavior of clients/server(s)
simulation problem:
Answer the following requirements
1- Construct discrete model, which includes (Process No., Inter-Arrival time, Departure time, Waiting
time, and service time) when NES discrete simulation is used.
2- How many server(s) and queue(s) are proposed to use in the one layer system network. You should
justify your answer.
3- Compute utilization, and draw your conclusion.
1) Discrete Model
P#
1
2
3
4
5
6
7
8
9
10
11
12
1/
0
0
1
0
0
2
1
0
0
3
0
0
D
2
5
6
6
8
9
9
10
11
12
13
13
W
0
0
1
4
5
3
4
5
5
3
4
5
S
2
5
4
1
2
3
1
1
2
2
2
1
2) Two servers and three queues are needed, where the maximum progression of waiting in one time
unit is 3 while the maximum decline of waiting in one time unit is 2.
3) Utilization= sum of Si/T’ = 13/7= 1.85 - need to add two servers.
Unfamiliar Part:
Objective: This part aims to show student capability to show system behavior on complex network.
Q3(5 marks): Assume that we have the following hybrid system network which includes three levels.
Perform Next Event Scheduling (NES) simulation technique on servers (2, 3) and using Activity Scanning (AS)
simulation technique on servers (1, 4, and 5). Let us define the following discrete model to find total waiting time
and utilization at each level.
Process No.
Inter-arrival Time
1
2
3
1
1
2
Service Time of any
Server
2
1
2
Check Time
2
1
0